Conventional high voltage half bridge driver integrated circuit may include a built-in bootstrap diode arranged between the low side supply voltage node VCC and the bootstrap supply voltage node VB, for connection with a bootstrap capacitor (not shown). During normal operation, energy is transferred from the low side power supply with nodes VCC and GND to high side supply decoupling capacitor between nodes VB and VS, via the bootstrap diode. However, in some applications it is preferable to integrate the bootstrap diode in the half-bridge driver integrated circuit for simplifying the application circuit. Such integration requires a diode with high reverse breakdown voltage that is normally not available in typical integrated circuit process technology platforms.
One solution is to use a diode emulator circuit having a high voltage LDMOS device to emulate the function of a diode. But the use of a high voltage LDMOS device usually requires complex eternal circuitry, which is not desirable.
There is a need to provide a simple, low cost solution to the above problems.